Percutaneous Closure of Patent Foramen Ovale (PFO)

Abstract

Patent foreman ovale (PFO) is common in the adult population with a prevalence of 25 %. The foreman ovale is an anatomical structure that develops during foetal growth which allows passage of blood from the right into the left atrium. In utero, it allows blood to bypass the inactive pulmonary circulation (Fig. 6.1). At birth, there is a rapid fall in right heart pressures as the lungs expand, in addition to a rapid rise in left heart pressures, causing the foreman ovale to close. In a proportion of individuals, there is inadequate closure and a PFO is maintained. Unlike other atrial septal defects, PFO represents a ‘flap’ type defect that can remain clinically quiescent until such conditions exist to allow the flap to be opened. Important clinical situations which cause temporary or permanent increases in pulmonary artery pressures are coughing or pulmonary hypertension.